This invention relates generally to injection molding and more particularly to an injection molding nozzle with heating element protective tubes extending outwardly through the collar.
Injection molding nozzles having an integral electrical heating element with lead portions extending outwardly into a radially extending terminal near the rear end are well known in the art. In the past, the components of these nozzles have usually been integrally brazed together in a one-piece structure having a rigid electrical terminal protecting against damage to the lead portions of the heating element. For instance, in the applicant's U.S. Pat. No. 5,235,737 which issued Aug. 17, 1993 the lead portions extend into metal connectors in a ceramic insulator which is surrounded by an outer protective steel sleeve screwed onto a rigid stud. In U.S. Pat. No. 5,266,023 to Renwick which issued Nov. 30, 1993 the lead portions of the heating element extend directly into a ceramic insulative connector which is similarly protected against damage by a protective outer steel sleeve screwed onto a rigid stud.
More recently, the applicants' Canadian Patent Application Ser. No. 2,127,211 filed Jun. 30, 1994 entitled "Injection Molding Nozzle with Removable Collar Portion" shows an injection molding nozzle with the lead portions of the heating element extending outwardly into a removable insulative connector without any protective outer sleeve. While this has the advantage of being less costly to make, it has the disadvantage that the relatively fragile protruding lead portions of the electrical heating element are not adequately protected against damage by the ceramic insulative connector.